1. Field of the Invention
This invention relates to a discharged ink treating method for a unit using an ink using portion such as a recording head for discharging liquid ink to thereby record an image on a recording medium, and an ink discharge device having a step or a mechanism for collecting into a liquid absorbing member or a collecting portion the ink discharged by pressing or suction to preliminarily discharge or recover the ink from the recording head as the ink using portion.
Also, the present invention relates to an invention which can be applied to a recording apparatus having the function of a printer, a copying apparatus, a facsimile apparatus or the like, or a recording apparatus used as the output instrument of a compound type electronic apparatus including a computer, a word processor, etc. or a work station, or an apparatus for recording images on a recording medium such as paper or a plastic sheet on the basis of image information.
2. Related Background Art
In a recording apparatus of the serial type adopting a serial scan system in which main scanning is effected in a direction intersecting the conveyance direction of a recording medium (the sub-scanning direction), the operation of recording (main scanning) an image by recording means carried on a carriage moved along the recording medium, completing the recording of a line, thereafter effecting a predetermined amount of paper feeding (pitch conveyance), and thereafter again recording (main scanning) the image of the next line on the recording medium stopped is repeated, whereby the recording on the whole recording medium is effected.
On the other hand, in a recording apparatus of the line type which effects recording by only the sub-scanning in the conveyance direction of a recording medium, the operation of setting the recording medium at a predetermined recording position, effecting the recording of a line in block, thereafter effecting a predetermined amount of paper feeding (pitch feeding) and further effecting the recording of the next line in block is repeated, whereby the recording on the whole recording medium is effected.
Of these recording apparatuses, a recording apparatus of the ink jet type (an ink jet apparatus) typical as a recording system using liquid ink is one in which ink is discharged from recording means (a recording head) onto a recording medium to thereby effect recording, and has the advantages that it is easy to make the recording means compact, that highly minute images can be recorded at a high speed, that recording can be effected on plain paper without the plain paper being subjected to any special treatment, and that running cost is low and noise is little because of the apparatus being of the non-impact type and moreover it is easy to record colored images by the use of polychromatic ink. Above all, an apparatus of the line type using recording means of the line type in which a number of discharge ports are arranged in the widthwise direction of paper can accomplish a higher speed of recording.
Particularly, recording means (a recording head) of the ink jet type which discharges ink by the utilization of heat energy leads to the ease of manufacturing one having a liquid pa th arrangement (discharge port arrangement) of high density by forming an electro-thermal conversion member formed as film on a substrate, an electrode, liquid path walls, a top plate, etc. by way of a semiconductor manufacturing process including etching, vapor deposition, sputtering, etc., and enables the apparatus to become more compact. On the other hand, there are various requirements for the material of the recording medium, and in recent years, it has become required that use can be made of thin paper and worked paper (such as punched paper for filing, perforated paper or paper of any shape) besides paper which is ordinary recording medium and resin sheets (such as OHP).
Generally, a recovery process for stabilizing the ink discharge characteristic of an ink jet head as an ink using portion used in an ink jet apparatus [the process of effecting ink discharge by suction from a discharge port through a hermetically sealing cap, the process of effecting ink discharge from the discharge port by the pressing from an ink supply side or the process of driving an ink discharging element by data for recovery discrete from data for recording to thereby effect ink discharge from the discharge port (hereinafter referred to as the preliminary discharge)] is carried out at a preliminary stage for image formation, at a predetermined period during image formation or after image formation, or at a predetermined period conforming to the period during which the apparatus is left unused, or at any timing.
An example of such apparatus will hereinafter be described with reference to FIG. 7 of the accompanying drawings. FIG. 7 is a perspective view illustrating an ink jet apparatus according to the prior art. A recording head 101 for discharging ink from a discharge port in an ink discharge surface 101a to thereby record an image on a recording medium 105 is carried on a carriage 102. This carriage 102 is supported by a guide shaft 103 for guiding the carriage in the direction of movement and is reciprocally moved while being opposed to the recording medium 105. The recording medium 105 is urged against a feed roller by a pinch roller and is conveyed by the feed roller being rotated. Further, after image formation, the recording medium 105 is discharged outwardly of the recording apparatus by a discharge roller. (The pinch roller, the feed roller and the discharge roller are not shown.)
Any foreign substance such as paper powder adhering to the ink discharge surface 101a and any excess ink are wiped off by a wiper 104 provided outside the image forming area (wiping operation). Also, a cap 106 and a suction pump are provided to prevent the clogging of the discharge port by covering the discharge surface 101a and to such the ink from the exterior of the recording head. In order to maintain and recover the ink discharging performance of the recording head, the above-described wiping and preliminary ink discharging operations are performed, for example, after the lapse of a predetermined time (e.g. 60 seconds) during the image output or at predetermined timing during the closing of a power source switch or the like. Also, the cap closing operation is performed, for example, before the cutting-off of the power source or after the lapse of a predetermined time (e.g. 60 seconds) after an image output signal is interrupted. Also, the ink sucking operation is designed to be performed a predetermined time (e.g. about three days) after or by the user's operation in order to remove any bubbles created in a head flow path with time. In the present example, the discharged ink discharged from the head is collected in a cassette, but alternatively may be discharged into a discharged ink receiving container provided in the apparatus or to a preliminary discharge area in which an absorbing member is located, and in such case, the discharged ink can reach a predetermined discharged ink absorbing member and be absorbed and retained thereby.
In the example of the prior art shown in FIG. 7, use is made of a construction (not shown) in which an ink cartridge itself having recording liquid ink in a bag is provided with a discharged ink absorbing member for absorbing and collecting the discharged ink. The details of this construction are described in Japanese Laid-Open Patent Application No. 4-211963 (U.S. Pat. No. 5,221,935 and EP Laid-Open Application 0442528). This publication recognizes the problem that when the discharged ink is directly given to the absorbing member, the ink absorbed in the absorbing member dries and the absorbing member cannot absorb the ink and the discharged ink in liquid state leaks from the ink cartridge, and solves this problem by increasing a portion in which the absorbing member can cope with the discharged ink.
On the other hand, in recent years, ink recording has been in the tendency that various additives are added to make the image quality characteristic after the recording with liquid ink good, and use has been made of ink which can shorten the time for which liquid ink solidifies and provides an image (i.e. ink excellent in adhering property).
Further, ink image has been regarded as more preferable if it is excellent in water-resisting property which refers to the degree to which image quality can be maintained against water such as rain and if it is excellent in light-resisting property which refers to the degree to which image quality can be maintained against light such as sunlight, but has been backward in the application to mounting. Ink development has been singly done to enhance such kind of performance, and water-resisting ink having many water-resisting dyes has been provided and pigment ink also excellent in light-resisting property has been provided.
However, even if as in the prior art described above, design is made to disperse the discharged ink receiving area of the ink absorbing member so as to enable the ink absorbing ability of the ink absorbing member itself to be utilized to its maximum, the use of the ink improved in characteristic such as water-resisting property, light-resisting property or adhering property has given rise to the following new problems.
That is, it has been found that before the ink itself is absorbed by the ink absorbing member, an increase in viscosity or adhesion takes place on the surface of the ink absorbing member and color materials such as pigments or dyes pile and the solvent in the ink remains and continues to pile among those color materials, thereby forming a heap. This phenomenon has been seen to cause a case where if as in the prior art, an attempt is made to collect the discharged ink from the last end portion of the discharged ink guide path of a suction pump or the like into the absorbing member, the deposition of ink in a heap state is formed between this last end portion and the absorbing member and that last end portion is shut up by the growth of the deposition of ink. Also, when the conventional preliminary discharge or pressing recovery is effected, the ink is discharged to a predetermined location and therefore, the growth of this deposition becomes remarkable. Particularly, when the recording means as the ink using portion is adapted for use with a plurality of colors, the discharged ink therefrom increases double and therefore the growth of the deposition thereof is remarkable, and it has been found that the more improved is the ink characteristic, the more remarkable becomes the growth speed.
Particularly, in a case where the ink jet recording head is of the scanning type or a case where the full line recording head is moved from a recording position to a position opposed to the absorbing member to thereby effect preliminary discharge so as to collect the discharged ink, it has been experienced that when the head is moved to the preliminary discharge area, that movement is disturbed or the surface of the head is injured to cause the problem of the head itself such as unsatisfactory discharge.
Also, in recent years, in contrast with the ink jet recording apparatus, there has been provided an apparatus in which different ink jet heads (for example, a plurality of color recording heads and a monochromatic recording head) are made interchangeable to thereby effect different records. However, when such different recording heads are used, the above-noted problem may not arise in the case of a single recording head, but yet may arise in the case of the ink of other recording head. Thus, it is preferable that as the apparatus body, design be made such that the above-noted problem will not arise whatever ink may come.